package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWork;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import org.springframework.aop.framework.AopContext;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;


/**
 * @author 86178
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder>
        implements IVoucherOrderService {

    @Resource
    ISeckillVoucherService seckillVoucherService;

    @Resource
    RedisIdWork redisIdWork;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠卷
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            //尚未开始
            return Result.fail("秒杀尚未开始");
        }
        //3.判断秒杀是否已经结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            //已经结束
            return Result.fail("秒杀已经结束");
        }
        //4.判断库存是否充足
        if (voucher.getStock() < 1) {
            //库存不足
            return Result.fail("库存不足");
        }

        Long userId = UserHolder.getUser().getId();
        //创建锁对象
        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        //获取锁
        boolean isLock = lock.tryLock(1200);
        //判断是否获取锁成功
        if (!isLock) {
            //获取锁失败，返回错误信息或者重试
            return Result.fail("不允许重复下单");
        }

        try {
            //如果直接使用 return createVoucherOrder(voucherId); 的话，不会让createVoucherOrder的事务注解生效
            //所以通过AopContext.currentProxy();获取代理对象(事务)
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
    }

    /**
     * 创建订单
     *
     * @param voucherId
     * @return
     */
    @Override
    @Transactional(rollbackFor = Exception.class)
    public Result createVoucherOrder(Long voucherId) {
        //5.一人一单
        Long userId = UserHolder.getUser().getId();
        //5.1查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        //5.2判断订单是否存在
        if (count > 0) {
            //用户已经购买过秒杀卷了
            return Result.fail("该用户已经购买过秒杀券了");
        }
        //6.扣减库存 利用了cas乐观锁
        boolean success = seckillVoucherService.update()
                //set stock = stock - 1
                .setSql("stock = stock - 1")
                //where id = ?
                .eq("voucher_id", voucherId)
                // and stock = ?
                .gt("stock", 0)
                .update();
        if (!success) {
            //扣减失败
            return Result.fail("库存不足");
        }
        //7.创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        //7.1订单id
        long orderId = redisIdWork.nextId("order");
        voucherOrder.setId(orderId);
        //7.2用户id
        voucherOrder.setUserId(userId);
        //7.3代金券id
        voucherOrder.setVoucherId(voucherId);
        //将优惠卷写入数据库
        save(voucherOrder);
        //8.返回订单id
        return Result.ok(orderId);
    }
}
